The fierce Kree warrior Phyla-Vell (the artificial offspring of Mar-vell) actually took on the Captain Marvel moniker for a short time before adopting the alias Martyr and later becoming an official member of the Guardians of the Galaxy.
As for the other bird that Kristen Stewart was hoping to nail with an superhero casting opportunity, one character who would help make that a reality is someone whom you may be surprised to learn is on the good side by appearance alone.
Therefore, there are enough ways already that Marvel can introduce this openly lesbian, cosmic avenger into the MCU franchise and her connection to a certain talkative mercenary in the comics could also pave the way for an alternate interpretation of said to character to find her way into the continuity.